In multi-modal or, more generally, multi-contrast imaging a plurality of images are furnished in different image channels. The contrast in those images usually corresponds to different physical properties of an imaged object or results from different manners of interaction of the object with the radiation used for imaging. There is prior knowledge in such systems that the images from the different channels relate to the same object. It has been noted by Applicant that very few approaches have been proposed in the past to use this prior knowledge in processing such images, for instance, in reconstruction or de-noising.
Although some recently proposed solutions make some inroads on this (see for instance D S Rigie and P J La Riviere, “A generalized vectorial total-variation for spectral CT reconstruction”, Proceedings of the Third International Conference on Image Formation in X-ray Computed Tomography, vol 1, No 1, pp 9-12, 2014), it has been observed that the fidelity of the reconstructed imagery on occasions falls short of expectations.